const fp = require('loadsh/fp');

// 数据
const cars = [
    { name: 'Ferrari FF', horsepower: 660, dollar_value: 700000, in_stock: true },
    { name: 'Spyker C12 Zagato', horsepower: 650, dollar_value: 648000, in_stock: false },
    { name: 'Jaguar XKR-S', horsepower: 550, dollar_value: 132000, in_stock: false },
    { name: 'Audi R8', horsepower: 525, dollar_value: 114200, in_stock: false },
    { name: 'Aston Martin One-77', horsepower: 750, dollar_value: 1850000, in_stock: true },
    { name: 'Pagani Huayra', horsepower: 700, dollar_value: 1300000, in_stock: false },
];

// 练习1
let isLastInStock = fp.flowRight(fp.prop('in_stock'), fp.last);
console.log(isLastInStock(cars))

// 练习2
let firstCarName = fp.flowRight(fp.prop('name'), fp.first);
console.log(firstCarName(cars))

// 练习3
let _average = function (xs) {
    return fp.reduce(fp.add, 0, xs) / xs.length;
}
// let averageDollarValue = function (cars) {
//     let dollar_values = fp.map(function (car) {
//         return car.dollar_value;
//     }, cars);
//     return _average(dollar_values);
// }
let averageDollarValue = fp.flowRight(_average, fp.map(car => car.dollar_value));
console.log(averageDollarValue(cars))

// 练习4
let _underscore = fp.replace(/\W+/g, '_');
let sanitizeNames = fp.flowRight(fp.map(_underscore));
console.log(sanitizeNames(['hello world', 'hello  lagou']));